In fields such as physiology, medical, and respiratory studies, it is often required to collect thermal data within the airways of a subject, such as a human, or other breathing animal. Such data can be used to obtain heat and mass transfer properties of the airway and tan be used in the evaluation of intra-airway vascular responses to environmental and pharmaceutical stimuli, by way of example.
The present invention provides a thermal probe which can rapidly acquire thermal and humidity data relative to inspired and expired breathing gas, including air, in the airway of a subject for evaluation purposes in such studies. Although the invention will be described with respect to a human subject, the apparatus is equally applicable for obtaining temperature and humidity readings within a conduit.
A temperature probe is provided for obtaining thermal measurements within a conduit such as the airway of a subject. The probe includes an elongated tube extending along a longitudinal axis and having a wire cage at the end which is inserted into the airway. At least first and second sensor arrangements are longitudinally disposed on the outside of the tube, within the confines of the cage, for obtaining an indication of airway humidity and temperature. In one embodiment each sensor arrangement includes a dry-bulb thermocouple and a wet-bulb thermocouple. A plurality of longitudinally disposed temperature sensors extend outside of the confines of the cage and are adapted to contact the inner surface of the airway for obtaining surface temperatures. All of the sensor outputs are coupled to an interface connector array whereby the output signals may be provided to an analyzing system. For measurements in the nasal airway, the cage portion may be reduced in size for insertion and thereafter expanded so that the sensors make contact with the mucous membrane of the nose.